A roller blind device for shade in a sliding roof of a motor vehicle is provided in EP 1 616 737 A1. The roller blind device has a flexible roller blind sheet held windably and unwindably on a winding shaft and provided at its front end area—when seen in the pulling-out direction—with a dimensionally stable pulling-out section. The roller blind sheet can be moved manually or using a motor between a pulled-out function position and a rolled-up rest position. To allow the roller blind sheet to be kept tensioned transversely to the pulling-out direction, and accordingly prevent sagging of the roller blind sheet, thin metal or plastic strips are assigned to the opposite lateral edges of the roller blind sheet and are guided in guide section arrays. The guide section array on each side is connected to a support frame in an elastically yielding manner by means of a connecting section fixed on the vehicle roof side. The elastically yielding connecting sections are elastically pretensioned in the function position of the roller blind sheet, in which the metal or plastic strips are guided inside the guide section arrays, so that a tensioning effect is exerted on the roller blind sheet transversely to the pulling-out direction.